Alternative Names

Causes, incidence, and risk factors

UPJ obstruction mostly occurs in children. It often happens when a baby is still growing in the womb. This is called a congenital condition (present from birth). The blockage is caused when there is a narrowing of area between the ureter and the part of the kidney called the renal pelvis. Urine can build up and damage the kidney as a result.

The condition can also be an abnormal blood vessel over the ureter. In older children and adults, the problem may be due to scar tissue, infection, earlier treatments for a blockage, or kidney stones.

UPJ obstruction is the cause of most urinary obstructions in children. It is now commonly detected before birth with ultrasound tests. In some cases, the condition may not show up until after birth. Symptoms may include an

Treatment

Surgery to correct the blockage allows urine to flow normally. Most of the time, open (invasive) surgery is performed in infants. Adults may be treated with less-invasive procedures. These procedures involve much smaller surgical cuts than open surgery, and may include:

Endoscopic (retrograde) technique does not require a surgical cut on the skin. Instead, a small instrument is placed into the urethra. This allows the surgeon to open the blockage from the inside.

Percutaneous (antegrade) technique involves a small surgical cut on the side of the body between the ribs and the hip.

Pyeloplasty removes scar tissue from the blocked area and connects the healthy part of the kidney to the healthy ureter.

Laparoscopy has also been used to treat UPJ obstruction in children and adults who have not had success with other procedures.

A tube called a stent may be placed to drain urine from the kidney until the surgery heals. A nephrostomy tube, which is placed in the side of the body to drain urine, may also be needed for a short time after the surgery. This type of tube may also be used to treat a bad infection before surgery.

Expectations (prognosis)

Detecting and treating the problem early can help prevent future kidney damage. UPJ obstruction diagnosed before birth or early after birth may actually improve on its own.

Most patients do well and have no long-term problems. Serious damage may occur in people who are diagnosed later in life.

Long-term outcomes are good with current treatments. Pyeloplasty has the best long-term success.

Complications

If untreated, UPJ obstruction can lead to permanent loss of kidney function (kidney failure).

Kidney stones or infection may occur in the affected kidney even after treatment.

Calling your health care provider

Call the health care provider if your infant has:

Bloody urine

Fever

A lump in the abdomen

Indications of back pain or pain in the flanks (the area towards the sides of the body between the ribs and the pelvis)

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